The development of mobile devices, in particular mobile phones, is characterized by different trends often having complex, interrelated implications.
One of these trends is the increasing need for multimedia capability, which includes high quality audio playback, be it for entertainment or for telecom audio. There is also the market's desire for integrated hands free speaker capability. These two needs can be met with high-quality integrated hands free speakers, which can for example be used for integrated hands free functionality, for playback of recorded audio, for frequency modulated (FM) radio playback, for high-quality playback of ringtones that are, for example compressed audio or digital audio files or for any other situation in which audio is generated by the mobile device.
Another trend is that in modern mobile phones the market demands antennas that are not visible to the user. The presence of an external antenna protruding from the housing of the mobile phone makes putting the mobile phone in a pocket less practical and is also unsatisfactory under aesthetic and design considerations.
Thus the antenna is regularly placed within the housing of the mobile phone. Both the antenna and the integrated hands free speaker, however, require a certain volume (three-dimensional space) within the mobile phone for physical reasons in order to be effective, volume which is becoming ever scarcer in increasingly miniaturized electronics. In fact, this often leads to placing the antenna and the integrated hands free speaker within the same cavity in the mobile phone. In addition, to achieve stereo effect, a mobile phone may comprise at least two integrated hands free speakers, thus further adding to the need for space in the device and concentration of such components within the same area. Just like for a phone antenna, a similar situation may also exist for a wireless local area network (WLAN) or Bluetooth® antenna. Thus the one or more antennas and the one or more transducers compete for the limited available volume that is shared by these different components. As a result, generally a compromise in the volume allocation between these competing requirements is made.
In a situation with such sharing of volume, the load caused by an integrated hands free speaker on the antenna is increased due to its proximity to the antenna and because a miniaturized, internal antenna has less favorable sensitivity characteristics than an antenna which is larger or external. This load on the antenna is detrimental to its operation. The severity of defect on the antenna depends on the mechanical design of the transducer as well as its location within the electronic equipment such as a mobile phone.